(a) Field of the Invention
The present invention relates to processed dried pulses which are almost instantaneously restored to the soft edible condition of boiled raw pulses. More particularly the invention pertains to such processed dried pulses are described above which can be restored in a very short period of time to their boiled soft edible condition simply by pouring hot water onto the processed dried pulses, and the invention pertains to a method for manufacturing such pulses.
In order to facilitate the understanding of the present invention, the word "pulses" will hereunder be substituted by the word "beans" which will signify collectively various kinds of pulses, throughout the specification and the claims.
The beans which are suitable for use in the present invention are those beans which are rich in starch and poor in both protein and fat.
(b) Description of the Prior Art
The methods for producing processed dried beans which quickly restore the soft edible condition of boiled raw beans, include the following known methods: (1) a method comprising first softening raw beans by boiling the beans together with a softening promoter such as polyphosphate to soften also their seed coat, and thereafter immersing the resulting softened beans in a solution such as a sucrose solution, followed by drying the resulting solution-treated beans in heated air; (2) a method comprising first boiling and softening raw beans, and then freezing the resulting beans and thereafter drying them in heated air; and (3) a method of producing processed dried beans by simultaneously freezing and drying the boiled softened raw beans in vacuo.
However, the processed dried beans produced in accordance with the above-mentioned known method (1) are not easily and quickly restored to their soft boiled condition by merely pouring hot water thereonto. Whereas, those processed dried beans produced in accordance with the method (2) mentioned above are not satisfactorily and quickly restored to soft boiled condition though these characteristics are improved a little as compared with those processed dried beans obtained by the method (1). Furthermore, those processed dried beans produced in accordance with the freezing-drying treatment of the method (3) lack their original flavor and natural good feel to tongue since the textures and tissues of the cells of the beans themselves have been indiscriminately destroyed during the freezing-drying treatment.
The inventors of the present invention have undertaken strenuous and extensive research and experiments to eliminate the above-discussed difficulties and disadvantages of the known instantaneously restorable processed dried beans, and at last they have successfully worked out the present invention.
As a result, it has been found that raw beans which have been defined as above and which can be used in making a paste of beans, can be converted to dry bean products which are easily restored to their hydrated state. The raw beans are first boiled at least once in a boiling water, and thereafter they are subjected to an enzymatic reaction (treatment with an enzyme) by immersing the boiled raw beans in an aqueous solution containing an enzyme which is either cellulase or pectinase or both, with or without subsequently subjecting the resulting beans again to boiling treatment at least once in boiling water; and thereafter the beans are dried. The enzyme acts on the pectic intercellular substances or acts on the cellulosic substances existing in the cell walls of the boiled beans to uniformly and effectively destroy the cell tissues existing in and around the seed coat and the epidermis of the seed lobe (catyledon) of each bean. The enzyme action improves the permeation of hot water into the core of each bean and improves the ability of the product processed dried beans to be restored to the condition of boiled beans immediately upon contacting hot water. In addition, the beans which have been processed in this way retain the original taste and flavor which are peculiar to the boiled raw beans (as represented by fragrance, the after-taste and sweetness, as well as an agreeable feel to tongue, agreeableness to taste, glutinousness, agreeable coarseness and the like,) when the dried beans are subjected to hot water to hydrate them to restore the boiled soft condition. Furthermore, it has been found also that the processed dried beans according to the present invention which are suitable for being used as what is called "instant food" can be manufactured advantageously on the industrial basis.